1. Field of the Invention
The present invention relates to electrodes for electrochemical analysis. More particularly, the present invention relates to electrodes that are drops of conducting liquids for use in making electrochemical measurements of sample solutions.
2. Discussion of Background
In electrochemical analyses, electrodes are used to cause an electrical current to flow through a sample of a solution of interest so that data characteristic of the sample solution can be obtained. Most electrodes used are solid, typically made of metal or other electrically conducting material. However, during repeated use, the surfaces of electrodes tend to erode, reducing the operational accuracy of the device. Further, electrode surfaces tend to accumulate foreign matter caused by the deposit of migrating ions.
Because of these problems, mercury is often used in electrochemical analyses. Typically, mercury, which is liquid at room temperature, is introduced into the sample solution one drop at a time. Thus, a fresh electrode surface is provided by each mercury drop, avoiding the problems of the degradation of the surfaces of solid electrodes.
For example, Ladisch, in U.S. Pat. No. 2,706,710, discloses a polarographic mercury cell used for measuring diffusion currents. His cell has an upper chamber of fritted glass through which mercury drops.
However, the use of mercury in such applications presents health and disposal problems because mercury is highly toxic and therefore requires careful handling and carries with it special disposal requirements. There exists a need for alternate liquid electrodes.